Short-range wireless proximity networks typically involve devices that have a communications range of one hundred meters or less. To provide communications over long distances, these proximity networks often interface with other networks. For example, short-range networks may interface with cellular networks, wireline telecommunications networks, and the Internet.
IEEE 802.15.3 defines an ad hoc wireless short-range network (referred to as a piconet) in which a plurality of devices may communicate with each other. One of these devices is called piconet coordinator (PNC), which coordinates timing and other operational characteristics for the network. The remaining devices in the network are known as DEVs. The timing of piconets is based on a repeating pattern of “superframes” in which the network devices may be allocated communications resources.
A high rate physical layer (PHY) standard is currently being selected for IEEE 802.15.3a. The existing IEEE 802.15.3 media access control layer (MAC) is supposed to be used as much as possible with the selected PHY. Currently, there are two remaining PHY candidates. One of these candidates is based on frequency hopping application of orthogonal frequency division multiplexing (OFDM). The other candidate is based on M-ary Binary offset Keying. The OFDM proposal is called Multiband OFDM (MBO). Moreover, in order to further develop the OFDM proposal outside of the IEEE, a new alliance has been formed called the MultiBand OFDM Alliance (MBOA).
MBO utilizes OFDM modulation and frequency hopping. MBO frequency hopping involves the transmission of each of the OFDM symbols at one of three frequency bands according to pre-defined code, referred to as a Time Frequency Code (TFC). Time Frequency Codes can be used to spread interleaved information bits across a larger frequency band.
Presently, there is an interest within the MBOA to create a Medium Access Control (MAC) layer that would be used with the OFDM physical layer instead of the IEEE 802.15.3 MAC layer. This would involve developing a new procedure for device discovery and connection setup. It is desirable for such a MAC to provide fast device discovery and connection establishment, because ad-hoc networks can be very dynamic and connections may change quite rapidly.
Before piconets are formed, packets (such as beacons) are typically transmitted and received by devices in order to setup a network. For instance, in IEEE 802.15.3 networks, beacons are sent at the beginning of each superframe. After sending a beacon, the device must listen for a predetermined time period to determine whether there are requests to join the device's network. A response to such a request is scheduled for transmission in the following beacons. Thus, they are sent in the following superframes. Accordingly, in IEEE 802.15.3, connection establishment is not performed immediately, even in situations where only two devices are involved.